Why Site Speed Optimisation Should Be Part of Your SEO&nbspStrategy

This YouMoz entry was submitted by one of our community members. The author’s views are entirely his or her own (excluding an unlikely case of hypnosis) and may not reflect the views of Moz.

In late 2010, Google publicly announced that site speed was a new signal introduced into their organic search-ranking algorithm. Despite the announcement, has not been an integral part of the SEO agenda and is still given a much lower priority than it deserves. Certainly, out of the box thinking in 2013 cannot be just about great content and natural links.

Improving a site’s page loading time can be a rather laborious task; it requires thoughtful planning, significant resources, benchmarking, flawless execution, thorough testing and evaluation. Particularly for enterprise sites planning and testing can take several months and requires collaboration between different teams. In many cases, it requires a great deal of technical skills which fall on web developers, system administrators, network specialists and other technically minded professionals. But does all that signify that page speed optimisation is a waste of time?

Why Page Speed Is Important For SEO

With the direction SEO has taken since Google released the Panda and Penguin updates, scalable link building is becoming increasingly costly and unsustainable. At the same time there has been a great shift to content marketing, however, the point should not be whether producing link-worthy content is the best SEO strategy moving forwards.

Even though I find most of Matt Cutt’s comments a bit flamboyant, one thing I 100% agree with is that digital marketers should think of SEO as being Search Experience Optimisation. That means that SEOs should no longer be optimising thinking of bots but users. Offering the best possible user experience is what engines are interested in, value and reward.

SEOs have an incredibly versatile skill-set to draw from when helping online businesses increase their revenues. They understand the way search engines crawl, index and rank content, how users behave when searching for or visiting a site. They can carry out correlation studies, prioritise keywords that convert better, devise and implement content strategies and detect issues in the source code that hinder spiderability. Last but not least, they can (or should) optimise websites for speed.

Site speed optimisation has traditionally been led by web developers and CRO experts, most of whom have little interest, knowledge or experience about search engine spiders’ behaviour. In addition to the obvious fact that enhancing user experience increases engagement, fast loading pages can also have some unique and essential SEO benefits.

How Page Speed Affects Indexation, Traffic & Rankings

In general, slow loading pages suffer from low user engagement (increased bounce rates, low average time on page) and if it is true that Google takes into account user behaviour data to influence search rankings, it can be argued that bouncing off a slow loading site could potentially decrease its rankings.

Slow loading pages can also have a direct negative impact on indexation. When search engines cannot crawl a site for a few days or weeks, rankings associated with the keywords of the inaccessible pages will start suffering, sooner or later.

Conversely, fast loading pages can improve indexation as Googlebot spends its time more efficiently when crawling a fast-loading site. Because Googlebot allocates each website a specific crawl budget (depending on various factors such as authority and trust), being able to download and crawl pages faster means that it will ultimately download and (in most cases) index a higher number of pages.

For large websites, indexation is key to success in Google’s organic search. Ecommerce websites with thousands of products and often millions of (duplicate) pages struggle to gain visibility for all their products. News websites that manage to index their latest articles fast usually cap the top rankings and see their traffic levels soaring.

Crawl budget optimisation is about:

Increasing the number of pages Googlebot crawls when visiting a site

Decreasing the size of each page Googlebot visits and downloads

Both of these two parameters can be heavily influenced by site speed optimisation. The idea behind the first argument is that if pages are loading faster, Googlebot will crawl (and hopefully index) more pages in each visit. Furthermore, making sure that Googlebot can download pages faster will allow it to visit and download more pages before using up its entire dedicated crawl budget and leave the site.

The bottom line is that getting more pages in Google’s index has the potential to increase traffic. Having more pages indexed means that there will be more keywords with ranking potential. On large, authoritative sites increasing the number of indexed pages alone is enough to bring more long tail keywords straight on to the first page of Google’s SERPs and because the tail on these sites consists of thousands of keywords, this is a big win.

Looking into this from a different perspective, increasing indexation on enterprise websites can be more beneficial than any link building campaign in terms of traffic and revenue gains. Page speed optimisation is scalable and improving the page loading times of the most common types of pages (e.g. homepage, category page, product page) will almost certainly benefit the entire site.

Slow Pages Kill Conversions

Several case studies have demonstrated that fast loading sites can significantly increase conversions and boost sales. In 2012, Walmart announced that conversions peak at around 2 seconds and then progressively drop as page loading time increases. In the follow graph, notice how dramatically conversion rate drops when page loading time increases from 0-1 to 3-4 seconds.

These two studies also agree with Akamai’s survey that found that 47% of online users were expecting pages on retail sites to load in 2 seconds or less back in 2009. In 2012, the percentage of tablet users expecting a website to load in 2 seconds or less reached 70%.

Many other organisations including Google, Yahoo, Facebook and Amazon have carried out their own site performance tests, all of which with very interesting findings. All these have been included into the more in-depth white paper ‘How Site Performance Optimisation Can Increase Revenue on Desktop and Mobile Sites’, which can be downloaded directly from the iCrossing UK site.

Site Performance on Mobile Devices Matters Even More

According to a report published by The Search Agency Google saw 25.9% of total paid clicks coming from mobile devices in Q4 2012. What is even more important is that the mobile phone industry is still growing and mobile search share is expected to keep rising. Compared to desktops, page loading times on mobile devices are higher due to latency, lower processing power, smaller memory and limited battery life.

In 2012 the size of the average web page exceeded 1MB. Our Research & Insight specialist Gregory Lyons estimated that at the beginning of 2016 the average web page size will have doubled, exceeding 2MBs. This means that site performance on mobile devices needs to be addressed separately, otherwise trying to download such big files on smartphone or tablet devices will increase latency further. With more and more websites adopting Google's recommended responsive design approach, page loading times of content heavy pages on mobile devices could increase to the point that users would just give up waiting and try a different SERP. Given that Google has acknowledged site speed as a ranking signal, it wouldn't be surprising if, overtime, it gets even more ranking weight in mobile SERPs. At the end of the day it is in Google's best interest to prioritise signals that make for a better user experience.

How to Identify Site Performance Optimisation Opportunities

Several tools and services can help with simulating or even monitoring site performance based on the actual visitors of a site. The former ones are known as Synthetic Measurement services and the latter as Real User Measurement (RUM) services.

Synthetic Measurement Services

These services are often free and available to anyone making them ideal to measure site speed on own as well as competitors sites.

WebPageTest.org is the most widely used service and within reason. It allows for multiple URL-specific tests from:

Multiple geographic locations (ideally this choice should be made based on your users’ most common locations)

Different browsers

Different connection types

Mobile devices

JavaScript enabled/disabled clients

The better the above parameters match the characteristics of the most common visitors, the closer you can get to what they experience when visiting your site.

Once the test is completed you get a summary table like the one below:

First view loading times include all measurements for first-time visitors (no cookies/no caching)

Repeat view loading times include measurements for visitors who have been previously on the same page (with cookies and caching enabled)

In order to assess which view is more important to speed up, you need to take into consideration the new Vs returning visitors split from analytics.

The ultimate objective is to reduce the time, number of requests and filesize so the page loads faster. Although getting into the details of the various ways to increase site performance is outside the scope of this post, there is a dedicated section in the aforementioned white paper (pages 9-11).

WebPageTest.org even makes specific recommendations and scores a site’s performance so even non -technically savvy SEOs can easily identify the main weaknesses of a website and start a conversation with the web developers.

Google’s PageSpeed Insights and Yahoo’s Yslow (both available for Chrome and Firefox) can also be useful if you need to run a quick site performance test on a specific page and figure out what may be missing. However, they do not go into as much detail as WebPageTest.org does.

Yslow performance score and recommendations

Pingdom Toold is another popular synthetic measurement service which runs regular checks on a list of given websites and monitors uptime and downtime. When outages do occur, the service sends email and SMS notifications.

Pingdom Tools monitored website downtime

Real User Monitoring Services

RUM services offer site speed measurements based on a site's actual visitors page loading times. These are tracked by adding some proprietary JavaScript code on every single page of a site, hence measurements are not possible for competitors sites. There are several (Free and Paid) RUM services available with the most common one being Google Analytics. Undoubtedly, combining site speed with business metrics such as pageviews , entrances, bounce and exit rates can provide some unique insights, which is the biggest strength of Google Analytics' site speed service.

However, the Google Analytics site speed feature comes with a few flaws with the main ones being the following:

The Navigation Timing API, which Google Analytics relies on to collect its site performance data, is not supported by all browser vendors. Some desktop browsers (e.g. Safari) as well as browsers for popular mobile devices (e.g. iOS) do not support the API, which is not ideal given the increasing popularity of mobile devices. The API seems to currently support around 65% of global users.

By default, sampled page timings come from 1% of the site’s visitors. For high traffic sites the maximum amount of sampled data would be 10K per day. However, for websites with less than 100K visits per day the default sample size may not be ideal.

For instance, according to the below sampled data the homepage of a site with low traffic levels seems to take 12.89 seconds to load. Because the page load sample comes from 19 visits out of 2469 pageviews the data accuracy is questionable.

Improving Google Analytics Site Speed Sampled Data

The good news is that it is possible to increase the site speed sample rate by specifying a higher percentage value for the _setSiteSpeedSampleRate() parameter. For instance, to increase the site speed sample rate from the default 1% to 50% the modified async code would be:

_gaq.push(['_setSiteSpeedSampleRate', 50]);

_gaq.push(['_trackPageview']);

There is a very useful and quick to install Site Performance dashboard for Google that provides a quick overview of the most useful page speed metrics.

For more accurate results some of the most popular 3d party RUM (yet not free) services include:

These services can offer real time site speed data with a lot more granularity on the actual visitors’ page loading times.

Page Loading Times Histogram (Torbit Insight)

Drill Down Interactive Graph (Torbit Insight)

Conclusion

Web Performance Optimisation or WPO (both terms formed by Google's Head Performance Engineer Steve Sauders) takes time and requires thorough planning and resources. However, as several case studies have shown faster loading pages strongly correlate to higher revenue. Because the ultimate goal in every SEO campaign is to maximise revenue, web performance optimisation does not fall out of scope.

As explained earlier, fast loading pages can increase traffic, pageviews and conversions as well as make users happy. Website owners who do not invest in site performance optimisation and treat it as an integral part of their overall digital strategy, run the risk of missing out on a big revenue opportunity. A fast loading site will not only help SEO traffic but also traffic from all other channels (direct, PPC and referring). If, you are still unconvinced, try Tagman's revenue loss calculator which can help forecast the estimated loss in revenue when page loading time is reduced from 1 to 3 seconds.

Note: For more facts, statistics and case studies as well as tips on the 10 best common areas to pay attention to when optimising for speed please refer to our ‘Slow Pages Lose Customers’ POV.

Update: Useful Wordpress Plugins To Improve Site Performance

Due to popular demand I’ve put together a list of plugins that can help improve site performance and reduce page loading times on Wordpress sites. You should definitely read the available documentation as well as thoroughly test each one of the plugins you’re planning to use to avoid conflicts with other plugins.

Reduce HTTP requests - JS and CSS Optimiser is a great plugin to reduce the number of HTTP requests. It combines all JavaScript or CSS code in just one file, where possible, which can significantly improve performance. SpriteMe.org offers a bookmarklet that helps grouping images into CSS sprites so the number of HTTP requests reduces further.

Use a CDN – There are quite a few different options when it comes to choosing a Content Delivery Network, some free and some paid.

jsDelivr.com is a free public Content Delivery Network (CDN) that hosts JavaScript libraries and jQuery plugins. The jsDelivr plugin allows to easily integrate and use the services of jsDelivr.com on any Wordpress site.

WP Booster is another CDN plugin solution for Wordpress sites which delivers CSS, JavaScript and image files from CDNs in different parts of the world.

Modestos Siotos is the Technical SEO Director of iCrossing UK. His main focus encompasses all aspects of technical SEO such as site migrations, e-commerce, mobile and international SEO . @Modestos_ posts regularly on various digital marketing blogs including Moz, Majestic SEO and Search Engine Journal.

Thank you very much for this share. Page Speed (as you mention) is vital for both SEO and user experience. I also think it goes hand in hand with Mobile SEO/Responsive Web Design in making sure that websites are on the best framework possible. It's a win-win all round. I personally am interested in achieving faster Page Speeds on Wordpress websites. We all know that Wordpress websites are naturally SEO friendly, but achieving the Page Speed (in addition) is equally important, as it also has the reputation of being slow "out of the box".

Certainly Wordpress sites can be very slow "out of the box" especially if they rely on many plugins. In fact, some plugins can even bring sites to a halt and cause more issues than resolve. This is a typical problem with most open source projects where several people of different programming backgrounds, skills and experience have been involved.

GTmetrix for WordPress is a nice plugin that actively keeps running site performance reports and sends alerts if your site falls below certain criteria.

Another typical culprits that slows down performance on Wordpress sites are the typical social sharing buttons plugins. Async Social Sharing, is a really cool plugin that resolves this by loading loads all popular social sharing widgets asynchronously after the page loads, which helps site performance.

Thanks a lot for your interesting reply, and it's nice to hear about the possible "edit".

As you said, it's well known that Wordpress websites are slow out of the box, however, there are some fantastic plugins available. As an "All in One" soluution, we have W3 Total Cache that can manage pretty much everything in terms of caching, minifying etc.

As an alternative to W3 Total Cache, there is WP Super Cache combined with WP Minify that can be quite powerful together.

I personally have not implemented a CDN yet, although I'm very keen to. Yoast recommends MaxCDN for Wordpress websites:

Thank you very much for the additional section on Wordpress plugins Modesto. There is actually a lot there that I haven't used so I look forward to implementing. I used to use W3 Total Cache (which was very effective) but unfortunately it conflicted with my website. It's a complex plugin, that's for sure.

Anyway, the list you've given is fantastic and could have made a post all by itself! Thank you.

Perfect timing!Recently we've been investing a lot of time into improving site performance, with development allocating a lot of resources to ensure we dropped below two seconds (previously we were above 4 seconds).We had been using New Relic throughout the trial period and found it to be quite insightful.I've passed this article onto the development team to read as it helps to re-enforce the points I have been making.Many thanks for this article. You've saved me some additional conversations.Mark

Mark, smart move new relic's awesome. I think with the tools that have been given here and I plan on writing You moz article on hosting right now. please look for it as I think there is a strong correlation. Front side optimization is beyond important server-side backside optimization is also beyond important.

May I ask what type of website running WordPress non-WordPress? and some of the basic steps you took to increase your speed for and since I need to make my DNS name servers running back on DynECT vs ultradns that are running on to try out but cost me in time. DNS only has a time delay the 1st time your site is accessed. I need to set up GEO routing on ultra to be sure I'm not wrong.Here is a disappointing one point something speed test on a 2 MB website that clearly needs more front end optimization

http://tools.pingdom.com/fpt/#!/DvyMnyXsr/www.blueprintmarketing.com

Hears a website I am still building however using better framework that on the 1st website believe gives me a strong advantage take a look at the differences. Note that because I chose to use the theme's demo there are quite a few pages of content that still need to be changed or deleted. But look at the speed and what the differences are and what needs to be changed

Mark, I'm pretty sure that making your sites pages load in less than 2 seconds is going to have a great impact on your pageviews and conversions. It would be great if you could give us an update on your findings when you get there.

Such a timely post for me as I started the process of getting my sites quicker to load last week and although strides have been made, there is plenty of room for improvement. Thanks for all the fantastic information!

Thanks so much. This is a key opportunity for my website and something I'm working on, so the timing is perfect. You are so right about the user experience - the less time loading, the more they'll read/more pages they'll go to. And, of course the load times for my site are slower for mobile, so I really need to address this over next month or two.

You can implement things to address it right away. For instance a content delivery network is never a bad place to start. Try out Max CDN, Amazon cloudfront, Rack space cloud files, cloudflare is free and will help with caching even using a service like Torbit Will speed up your website starting now.If your not using a CDN I recommend using one now.

Real User Monitoring Services

will set the benchmark for you telling you where you are right away and there's no reason you can't implement them right now. I think Pingdom is great but Verelo gives you more and for free for a limited time.

Thanks for the suggestions Thomas. I've never used Verelo but I will definitely check it out. Choosing a reliable CDN is certainly one way to improve site performance although not the only one. I find that before choosing a CDN it is worth estimating/forecasting the total cost because for some sites a CDN can end up being quite costly. As I mentioned in the post, in my paper 'Slow Pages Lose Users' I have included a section on the 10 most common areas to pay attention to when working on web performance optimisation.

Amen Modesto! When we were putting together our SEO projects for 2013, I did a lot of research on the potential ROI of each proposed project. I initially thought that CRO would be our biggest potential ROI project but I was wrong. WPO blew all the other projects our of the water in terms of potential ROI. Now given, this has a lot to do with how slow our site is right now, so the potential for improvement is massive. If we already had a blazing fast site, that might not be the case.

I found the Walmart data pretty compelling. Thanks for an awesome post and more fuel for my WPO project :-)

Thanks Dana. I'm not surprised Web Performance Optimisation had the highest potential ROI in your case. In my experience not many budget holders consider investing in WPO but hopefully this trend will change over time.

Getting pages to load in less that 2 seconds is definitely a challenge especially on pages with rich-media content. On the other hand we shouldn't get obsessed with numbers because everything is relevant. For instance, a page loading in under 2 seconds for one user could take twice as long for someone else on a slow internet connection.

Nice post Modesto.Google made it clear that site speed is a ranking factor. Also, you should make your site as fast as possible to prevent users from clicking "BACK" button before page loads. Nobody likes to wait for slow page to load.Thanks for post!

Love the analytics dashboard and the WP plugins. I knew most of them but I'm excited to try a few. The analytics dashboard helped me discover that my redirect time in the US is 0.18s when it's 0.02 in canada and in most countries. Got some digging up to do!Thanks again!

Surely not. If anyone try to use all the recommended plugins at the same time page loading times will almost certainly increase. I thought to offer readers more options so they can try and choose what suits them best. Certain plugins wouldn't work on older Wordpress installations, so I thought to offer a few alternatives.

Great Article Modesto!Site speed is such an important factor of a good SEO campaign now and conversion campaigns (if the site doesn't load within 5 seconds 80% of users won't visit the site) I use cloudflare to support my sites for 24/7 Site uptime and speed optimization, as well as preventing malicious attacks.

We have been using the Google Page Speed Servicehttps://developers.google.com/speed/pagespeed/The results on http://www.webpagetest.org are brilliant.However we are facing a few problems:1) Occasional downtime as using proxy server.2) Huge amount of extra source code added when using view source.3) Can’t have IP dependant functionality on website because using a proxy server.4) Problem with PCI compliance for credit cards.I would like advice on whether to remove the Page Speed Service or work on minimizing the problems.

Search experience optimization sounds so much better than search engine optimization. Don't you agree? Only quality brand mentions on niche sites, consistent content production and website performance optimization could help businesses get the most out of search. Great post.

Yes, a superb article, very informative. It is about time we were all more aware of the relationship between speed and SEO. I guess it is an obvious strategy for Google. Of course faster sites will be have a more positive user experience but I bet many web managers don't measure site speed as key metric.

Thanks for sharing this post. It is really very valuable information. I was aware that site speed could effect user experience, and also increase bounce rate but wasn't really aware that it effects the conversions to this extend.

This is a very good post, but I just want to ask, is the 0-2 second can be considered as the average site speed for a good page? Another thing I want to ask is that, how much memory would you recommend for a site to address the problem regarding with the size of images, videos, etc, and can a site maintain a certain speed for a certain time? If not, what could be the reasons behind it? Thank you for a very informative post :)

I've been going crazy with page speed optimization this week. Writing a few posts about the things that generally cause slow load and one of the major factors has been image resizing.

If your using WordPress then Jetpack has a module called "Photon" that resizes your images AND serves them from the WordPress CDN. If you've already installed Jetpack then it's a 1 click activation and set up. :D The resize and CDN implementation in one gives a mega speed boost for your site and it's probably worth a mention in the WordPress plugins section.Another thing worth mentioning is mod_pagespeed. With just the default filters enabled one of the sites hosted on the server went from 42 seconds load down to 7 seconds. 6 times faster with just executing 3 lines of code on the server. Pretty nice result :D

This is a very thorough and highly valuable article - a real service to the SEO community. I've experienced problems with site speed in the past, as revealed by WebPageTest.org. It's one of the most frustrating elements of SEO because it is completely out of my control. When I mention it to my web designer (who is in control of site speed), he uses Pingdom and gets a completely different result. Has anyone else had this problem in the past?

All synthetic measurement services would give different results depending on the chosen configuration (location, speed, browser) but what is really important is to measure site speed from a location which is typical for the majority of your visitors. If your business is in the US most visitors would presumably come from the US. However, measuring site speed from a European location the results won't be reflect your audience's experience.This is where a RUM service would be more reliable because you could measure performance as experienced by the site's visitors. Either, Google Analytics or any other of the RUM services mentioned in the post would eliminate the possibility of site speed discrepancies.

Definitely. The main reason I prefer using WebPageTest instead of Pingdom is because I often work on UK-based sites. Unfortunately, Pingdom only measures site speed from 3 locations: New York, Dallas and Amsterdam, none of which is ideal for UK sites.

Geordie, when I was writing the post I totally overlooked Wordpress as I hardly ever work on Wordpress sites these days. However, I've put together a list of Wordpress plugins which have now been added as a bonus section at the end of the post.

Great post I could not agree with you more and really appreciate you writing this as I was about to put something together for my clients when they say "oh you think a second or two matters" I get depressed and explained to them why it is more than just what Google tells you its importance is but what true real-world conversion rate as you've put so well really matters. If the site does not load after I'm guessing 4 seconds I think there something wrong and I'm gone unless I really really want to be on that site for some reason. the faster site loads the more trust I have in their brand believe it or not I actually do gauge their website by how it performs as far as the quality of the brand for some reason those two things matter to me. some more tools I like to use are listed below some of you guys I am sure very familiar with them however if you're not check them out.I love new relic andhttp://torbit.com/insight/They're both indispensable here are a few more tools everyone should use.there's a tool called Verelo they will tell you your site speed and port speeds all over the world and outstanding application. I got an e-mail telling me "I'm sorry guys we gave it our best but unfortunately we will be are closing our doors" I am a very happy Dyn.com customer and the next day received an e-mail saying we have purchased Verelo I could not have been happier and strongly recommend it. Here's the link http://www.verelo.com/ and the best news if you sign up now it's free.http://gtmetrix.com/

I hope this gives everyone some more ways of testing and you become speed junkies not in the bad sense.I want to say thank you again for this excellent post. I wish we could talk to a little bit more I bet the blog would get more hits. Wink wink Tom

In my experience relying only on Synthetic Test services (like the ones you mentioned) does not always offer sufficient information about the actual visitors' site performance metrics. Trying using a RUM service can provide additional insights and more granularity in most cases.

I've been working on this for my sites. Thanks for offering some new tools to try. I've been using Pingdom's speed test, but that doesn't offer the break downs like Y!slow does. I'm excited to get that installed to do some testing. I also like the term Web Performance Optimization. That kind of helps me get my mind around what it is exactly that I'm doing. It's also a way to tell my boss I'm using my time wisely.

Do you think this should be my main concern? I pretty much wear all the hats when it comes to running the web sites I work on so time is important. Our sites aren't slow, but they could always use a boost I imagine.

Both PageSpeed Insights and Yahoo’s Yslow provide a lot of technical details and recommendations. However, better accuracy and more granularity I'd recommend trying WebPageTest.org which also offers detailed break-downs.

In terms of how to justify the time you spend on WPO, the potential ROI of the investment should be your best bet. I'd also recommend trying the Tagman's revenue gain estimator, especially if you work on an ecommerce site.

Modesto, as all comments mention this is a great resource and insight for all of us...load time is first on my list for 2013 and I know my issues and am attempting to address them...Will use webpagetest.org in the future and have been using pingdom tools. Such an important discussion to have a returning visitor! thank you